Delay system



Feb. 26, 1963 l. KABIK 3,078,799

DELAY SYSTEM Filed sept. 29. 1960 lll/111111111 INV EN T IIIlIllllllll-LlRvlNs K K l ATTYS.

Unite rates The invention described herein may be manufactured and usedby or for the Government of the United States of America forgovernmental purposes without the payment of any royalties thereon ortherefor.

This invention relates to an improvement in fuses and more particularlyto an improvement in the method of holding and igniting a time delayfuse train.

Heretofore it has been common practice in a vented fuse to provide aninitiator plug on one end of the fuse, a time delay fuse column on theother with a chamber in between having vent holes for allowing the gasesto escape. This construction did not always achieve the desired resultfor the following reasons:

(l) Part of the hot gases utilized in the fuse initiator to ignite thefuse train escaped directly out of the vent holes on ignition withoutcoming into contact with or igniting the delay fuse train; and

(2) Possible separation in the delay fuse column due to a decrease indensity exhibited by the products of combustion of the gasless delaycomposition, the separation resulting primarily due to the evolved gasesacting against the unsupported column.

Any separation in the fuse delay column may result in extinction of theburning of the column, resulting in a dud unit.

The general purpose of this invention is to provide a time delay fusewhich embraces all the advantages of similar prior art devices butpossessing none of the aforedescribed disadvantages. To attain this, thepresent invention contemplates a unique single continuous column therebyavoiding any separation of the delay fuse column, a labyrinth path forthe initiating hot gases, combined in such a manner so as to assureignition of the delay column before venting. The porous disk also allowsan escape path for any gases given off by the delay powder.

An object of this invention is to provide a fuse with a new and improveddelay fuse column having a uniform density.

Another object is to provide a new and improved fuse having all parts incontinuous Contact during ignition and burning.

A further object is to provide a new and improved positive method ofigniting the delay fuse train prior to venting of the igniting gases.

A stili further object is to provide a unique construction formaintaining the delay powder in a compressed condition while allowingthe gases given off by the delay powder a path of escape.

Further obiects and the entire scope of the invention will becomefurther apparent in the following detailed description and in theappended claims. The accompanying drawing displays the generalconstruction and operational principles of an embodiment of theinvention. It is to be understood, however, that the drawing isfurnished only by way of illustration and not in limitation of theinvention and in which the single ligure is a side elevational view ofthe invention showing the general construction of a preferred embodimentthereof.

Referring now to the drawing, there is illustrated a time delay fuse il.The time delay fuse fil has an initiator assembly l2. which comprises aninitiator plug 13. The plug 13 may be made of any insulator material,for example, a phenolic, or Kovar glass, depending upon the atet f yintensa Patented Feb. 26, 1963 "ice design. Plug 13 has a pair ofelectrical contacts 14 extending therethrough which are connected to abridge Wire i5. The initiator plug 13 is snugly seated in a chargeholder 16. A charge 17 is centrally located in the charge holder 16 andin contact with the bridge Wire 15. The charge holder i6 has a chimney18 which is designed and seated on the porous disk 23 so as to allowgases to be vented from the delay body within which it will be used. Thechimney 18 also directs the hot gases from the blast of the charge li ofthe initiator assembly l2, past the vent holes 19, in the fuse container2li, through the porous disk 23 to the next succeeding explosiveincrement. The charge 17 in the charge holder 16 may contain variousmixtures 2l, for example, lead styphnate surrounding the bridge wirefollowed by an ignitor mixture Z2. The initiator assembly l2 is placedupon the porous disk 23 in the uper end of fuse container 2i). The fusecontainer it may be either crimped or soldered onto the initiator plug13 substantially as shown. The delay powder 24 is the so-called gaslesspowder and may be loaded from the other end of the fuse container. Agasless powder for example, is composed of a barium chromate, leadchromate and a manganese mixture. A heat sensitive powder .25 which iswell known to those skilled in the art is located adjacent to or may bepressed into the pores of the porous disk 23 followed by the delaypowder 24 having a time delay characteristic which is pressed into thecolumn until a predetermined height is achieved dependent upon thedesired delay time. This is followed in the order named by a similarheat sensitive igniter material 26, a forced litted slotted baille 27,another heat sensitive igniter material 2.3, a base charge 29 and acopper disk 30 which is crimped over the bottom of the container tocomplete the delay fuse. The delay charge may, for example, be anactuator charge, a propellant charge or a detonator. The upper and lowerends of the container are to be interpreted with reference to thedrawing.

When suiiicient electrical energy is passed through the wire bridge l5,the temperature of the wire is raised high enough to initiate the leadstyphnate 2l. This in turn initiates the ignito-r mixture 22 causing thehot particles and gases to pass down the chimney 13 into and through -alabyrinth path in the porous disks Z3 thereby initiating the nextignitor increment 25 and then passing out the vent holes i9 in thecylinder. The small amount of gas formed by the delay charge also willpass out of the porous metal disk 23 and through the vent holes 19.

The delay powder 24 is pressed to a uniform density and held in place bythe slotted baflle 27. As the delay powder 24 burns it tends to expandhaving a residue or slag material which is compressed by the porous disk23 rand slotted baffle 27 into the same volume as the powder originallyoccupied. The residue products of combustion of the delay powder 24would in the absence of such confinement be substantially less densethan the delay powder 24 thereby occupying more volume and would tend tosepara-te if it was not held in place by the porous disk 23 and slottedbaffle 27.

The porous disk 23 thereby provides support for the delay column so thatit cannot separate and at the same time allowing any gases resultingfrom the burning powder to escape. A heat sensitive ignition powder 26and Z8 is loaded on both sides of the baille 27 to ensure that the fusewill continue to burn through the bathe 27. The base charge 29 may beused to explode a larger device or operate a switch as shown in acopending application Serial Number 62,511, filed October 13, 1960.

The porous disk Z3 is composed of stainless steel sintered materialwhich may be obtained in various porosities. The porosity found mostsuitable for this application is P.S.S. grade c with a mean pore openingof microns.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

l. An electrically detonated time delay fuse for an explo-sive device,said fuse including a container having apertures located therein, anelectrical initiator means located in one end of said container forinitiating the fuse column when energized, a chimney type charge holderlocated in said container and partially surrounding said initiatormeans, a cha-rge located in said charge holder and responsive to saidinitiator means when energized, a porous disk of substantially the samearea as the inside area of said container and in contact with saidcharge holder, a gasless time delay powder column located in saidcontainer adjacent -said porous disk, a slotted balile restraining saidgasless delay powder at a uniform density between said porous disk andsaid slotted barile before initiating the fuse, said vslotted bafe andporous disk maintaining the unburned portion of said gasless delaypowder at a uniform density after initiating the fuse, a disk sealingthe end of said container and forming a chamber between said slottedbattle and said sealing disk, base charge means located in said chamberand ignitible by the burning of said time delay powder, said electricalinitiator means igniting said charge means causing the hot gases to ilowdown the chimney through a plurality of labyrinth paths in the porousmaterial thereby igniting the delay powder before being vented out theapertures in said container.

2. A time delay fuse for an explosive device comprising a containermember for holding the component parts of the fuse in continuous contactwith each other and having venting apertures therein, an initiator meanslocated at one end of said container member for initially igniting saidfuse, a chimney-type charge holder located in said container and incontact with said initiator means, a charge located in said chargeholder in contact with and responsive to said initiating means forcreating a large quantity of hot gases when ignited, a porous disk presstted in said container and in contact with and closing the exposedportion Iof said chimney-type charge holder in such a manner that thehot gases flow through the porous disk to reach the venting apertures 0fsaid container, a slotted baille, a time delay charge of a predeterminedlength held at a uniform density by said slotted baille at `one end andsaid porous disk at the other end of said delay charge before ignitionof said fuse, said slotted bathe and porous disk maintaining theunburned portion of said delay charge at a uniform density afterignition of said fuse, a metallic disk closing the other end of saidcontainer and forming another chamber at said other end thereof, a basecharge located in said chamber and ignitible by said delay charge foractuating the explosive device.

3. A time delay fuse for actuating an explosive device comprising acontainer having a plurality of apertures tainer, a time delay chargelocated in said container and held compressed at a uniform densitybefore ignition against said porous disk and being ignited by said hotgases passing through said porous disk, a slotted baffle for maintainingthe unburned portion oi said delay charge at a uniform density afterignition, said slotted bale forming -achamber with a metallic disk atthe other end of said container, and a base charge completely fillingsaid chamber.

4. A time delay fuse for an explosive device comprising a containerhaving apertures therein, a base charge in said container, a time delaycolumn adapted to ignite said base charge, a porous disk means forholding the time delay column at a uniform density before ignition andmaintaining the unburned portion of said delay column at a uniformdensity after ignition, said porous disk providing an igniting path tosaid delay column, an initiating means for providing a quantity of hotgases which are forced through said porous disk prior to being ventedthrough the apertures in said container' thereby igniting said timedelay column.

5. A time delay fuze according to claim 4 in which the initiating meansincludes an electrical initiator plug, a chimney-type charge holderhaving one end thereof mounted on said porous disk means, a chargelocated in said holder for giving oit hot gases when ignited, saidelectrical initiator being mounted on theother end of said charge holderand in contact with said charge whereby when said charge is ignited bysaid electrical initiator the hot gases pass down the chimney-typecharge holder through the porous disk to ignite said time delay column.

6. A fuze for an explosive device comprising a container havingapertures therein, a base charge located in one end of said container,an actuator train located in close proximity to said base charge andadapted to ignite said base charge, a baiile plate located between saidbase charge and said actuator train, a disk of sintered material forinitially compressing said actuator train to a uniform pressure betweensaid disk and said baffle plate, an electrical initiator plug located inthe other end of said fuze, a pair of electrodes extending through saidplug into the fuze, an electrical responsive bridge wire connectedbetween said pair of'electrodes, an initiator charge located in closeproximity to said bridge wire and responsive thereto for generating aquantity of hot gas when ignited, a chimney type charge holder with oneend incasing said charge and one end of said plug and the other end ofsaid charge holder abutting said disk whereby the hot gas of Vtheinitiator charge is directed by the charge holder into and through thesintered material to ignite the actuator train.

7. A time delay fuze for an explosive device comprising a cylinderhaving a bore along the longitudinal axis thereof, said cylinder havinga plurality of apertures normal to said bore and connected thereto, abase charge located at one end of the bore, a time delay column adjacentsaid base charge and adapted to ignite said charge, a sintered diskmeans for compressing said delay column and providing an igniting pathto said delay column, an initiator means located at the other end of thebore for generating a quantity of hot gases, and a chimney-type chargeholder with one end incasing one end of said initiator means and theother end abutting said sintered disk means, said charge holderdirecting all the hot gases into and through a plurality of labryinthpaths in said sintered disk to ignite said delay column.

8. A fuze ior an explosive device comprising a cylinder having a borealong the longitudinal axis thereof, an initiator means located in oneend of the bore for initiating the fuze when energized, a chimney-typecharge holder Vlocated in the bore with one end partially surroundingVsaid initiator means, a charge means located in said charge holderresponsive to said initiator means for generating a quantity of hot gas,a porous disk of sintered material of substantially the same area as theinside area Vof the bore and abutting the other end of said chargeholder, a slotted baiiie located near the other end of said bore, a timedelay column compressed to a uniform density between said porous diskand said slotted bale, a disk sealing said other end of the bore andforming a chamber between said slotted baille and said scaling disk, anda base charge located in said chamber and ignitable References Cited inthe le of this patent UNITED STATES PATENTS Bacon June 17, 19,30McKnight Jan. 20, 1959

1. AN ELECTRICALLY DETONATED TIME DELAY FUSE FOR AN EXPLOSIVE DEVICE,SAID FUSE INCLUDING A CONTAINER HAVING APERTURES LOCATED THEREIN, ANELECTRICAL INITIATOR MEANS LOCATED IN ONE END OF SAID CONTAINER FORINITIATING THE FUSE COLUMN WHEN ENERGIZED, A CHIMNEY TYPE CHARGE HOLDERLOCATED IN SAID CONTAINER AND PARTIALLY SURROUNDING SAID INITIATORMEANS, A CHARGE LOCATED IN SAID CHARGE HOLDER AND RESPONSIVE TO SAIDINITIATOR MEANS WHEN ENERGIZED, A POROUS DISK OF SUBSTANTIALLY THE SAMEAREA AS THE INSIDE AREA OF SAID CONTAINER AND IN CONTACT WITH SAIDCHARGE HOLDER, A GASLESS TIME DELAY POWDER COLUMN LOCATED IN SAIDCONTAINER ADJACENT SAID POROUS DISK, A SLOTTED BAFFLE RESTRAINING SAIDGASLESS DELAY POWDER AT A UNIFORM DENSITY BETWEEN SAID POROUS DISK ANDSAID SLOTTED BAFFLE BEFORE INITIATING THE FUSE, SAID SLOTTED BAFFLE ANDPOROUS DISK MAINTAINING THE UNBURNED PORTION OF SAID GASLESS DELAYPOWDER AT A UNIFORM DENSITY AFTER INITIATING THE FUSE, A DISK SEALINGTHE END OF SAID CONTAINER AND FORMING A CHAMBER BETWEEN SAID SLOTTEDBAFFLE AND SAID SEALING DISK, BASE CHARGE MEANS LOCATED IN SAID CHAMBERAND IGNITIBLE BY THE BURNING OF SAID TIME DELAY POWDER, SAID ELECTRICALINITIATOR MEANS IGNITING SAID CHARGE MEANS CAUSING THE HOT GASES TO FLOWDOWN THE CHIMNEY THROUGH A PLURALITY OF LABYRINTH PATHS IN THE POROUSMATERIAL THEREBY IGNITING THE DELAY POWDER BEFORE BEING VENTED OUT THEAPERTURES IN SAID CONTAINER.